Police officers stand around a structure built the night before by 'Occupy DC' protesters on McPherson Square in Washington, D.C., Dec. 4.

From NBC Washington:

Police have made arrests after members of the "Occupy DC" protest group constructed a wooden structure without a permit in McPherson Square overnight.

Park Police and DC police initially gave protestors one hour to dismantle the structure, but their request was refused. A few protestors began scuffling with police, after which arrests were made. Officers on horseback were also seen pushing the crowd back. A group of six protestors were seen on the roof of the 30-foot-high building while police kept the crowd back with caution tape and tore out pieces of wood from the bottom of the structure. 15 other protestors were seen inside the structure. More arrests were made after protestors attempted to break through the tape to aid the protestors on the roof.

Shortly after noon Sunday, the protest group reported that three arrests had been made, according to Tim Craig of The Washington Post. However, that number was likely to increase as the afternoon went on.

Police have closed the Vermont Avenue entrance to the McPherson Square Metro station. I Street between Vermont Avenue and 15th Street is also closed, as is the 900 block of 15th Street and the 800 block of Vermont Avenue.

An unidentified protestor is arrested in McPherson Square in downtown Washington, D.C., Dec. 4. U.S. Park Police are arresting 'Occupy DC' protesters who are refusing to dismantle an unfinished wooden structure erected in the park square overnight.